Lubricant for wire drawing



Patented Aug. 13, 1929.

UNITED STATES 1,724,134 PATENT OFFICE- CHARLES V. IREDELL, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR 'IO WESTINGHOUSE LAM]? COMPANY, A CORPORATION OIE PENNSYLVANIA.

LUBRICANT FOR WIRE DRAWING.-

No Drawing.

My invention relates to the art of wire drawing and particularly to a lubricant and method whereby the drawing operation may be facilitated and the die wear reduced.

In the manufacture of tungsten wire, the mechanical working of the metal is done while the wire is hot. The working process requires a gradual reduction in the diameter of the wire which means the employment of numerous swaging and drawing dies before the wire is reduced to the required diameter. In working the metal it has been the practice to lubricate the exceedingly hard tungsten metal by means of graphite held in suspension in a vehicle such as agar agar or other suitable suspending medium, in order to facilitate the drawing operation and to reduce die wear. The wire is frequently lubricated throughout the drawing operation and to this end the lubricant is circulated to the working apparatus. Since the graphite settles out from the suspending mediumif allowed to stand any great length of time it has been found essential to agitate the lubricant at frequent intervals. The circulation of the lubricant as well as its agitation causes the lubricant to foam and when in such condition circulation of th lubricant is difficult. I I

The present invention provides an immovement in that the tendency for the graphite to settle out is minimized and the foaming prevented.

Therefor it is an object of my invention to improve the properties of graphite lubricants :55 to the extent of preventing the graphite from settling out.

Another object is to provide awire drawing lubricant having a better state of suspensign of the lubricating material.

Another object of mv invention is to provide a Wire drawing lubricant which does not foam.

Another object of the invention will become apparent from the following detailed description.

In United States Patent 1,409,658, issued March 14, 1922, is disclosed a wire drawing lubricant consisting of fine particles of graphite held in suspension by means of a gelatinuous vehicle such as agar agar. Although this lubricant has been found very satisfactory I have found that its properties may be improved by adding thereto a substance which will change the physical state of 5% mixture. More specifically I improve the tion. A- solution of Turkey Application filed. September 29, 1926. Serial No. 138,574.

properties by incorporating in the material a substance such as Turkey red oil which will decrease the surface tension and thereby improve the suspending properties of the vehicle and decrease materially the tendency to foam. The following proceduremay be followed in preparing a lubricant embodying my invention and suitable for the purposes indicated above. 550 grams of dry agar-agar may be weighed out and allowed to soak over night in about 10 liters of water. To this mass about 8 liters of distilled water may be added and the mixture boiled until the solution is complete. The boiling solution is then poured into a ball mill and diluted With distilled water to a total volume of 26 liters. To this solution is added about 2200 grams of graphite and about 10 pounds of brown sugar and the mixture then ball milled for about 72 hours. At the end of this period, 5 liters more of distilled water are added and the milling continued for approximately 2 hours. For use in fine wire drawing, this solution may be further diluted with one quart-of distilled water for every three quarts of the solured oil is then made up by using about 50cc. of distilled water and one pound of turkey red oil which are placed together in a beaker. Aqua ammonia is added drop by drop with stirring until a clear solution is obtained. This clear solution is then added to the solution of agaragar and graphite, the usual quantity of the clear solution being equal to from about .7 5 to 1% by volume of the agar-agar and graphite solution.

A specific example of a suitable lubricant prepared in accordance with my invention is as, follows. A mixture of fine particles of graphite and agar agar is prepared by boiling the latter with sufficient water to give a jellylike consistency. This 'gealinous mass is mixed with powdered graphite and to this mixture is added about .75 to 1% by volume ofTurkey red oil. The entire mass is thoroughly mixed and may then be used for lubrieating purposes without the graphite settling out or foaming occurring. In order to obtain a thorough distribution of the Turkey red oil through the gelatinous mass, I find it preferable to add ammonia to the Turkey red oil in such amout as to give a clear solution of the oil. As indicated above, the Turkey red oil is added to distilled water and to this mixture is added aqua ammonia, drop by drop 110 until a clear solution is obtained. The Turkey red oil may then be added as indicated above. 7

The follo win g tests indicate the improvement obtained by utilization of my invention, the composition of the solution referred to in the following table consists of about 550 grams of agar-agar, 22;)0 grams of graphite, 10 pounds of brown sugar and about 42 liters of water: i

Sam-

Total volume of Percentage of 0ll P solution Turkey red on by volume Cubic centimeter Cubic centimeter Per cent 1 500 0 0.0 2 500 1 0.2 3 600 3 0.6 4 500 5 1.0

Settling test perceat graphite remaimngin suspension Hours settled'Sample No. 1 Sample No. 2Sample N o. 3 Sample No. 4.

Per cent Per cent Per cent Per cent 0 100 100 10 100 65 71.2 82.4- 87.7 92.9 61 57.0 7425 77.1 V 87.7

It is apparent from these data that a change has taken place in the ordinary graphite agar agar lubricant by the addition thereto of certain quantities of Turkey red oil, which not only prevents the material from foaming, but also exerts a very marked effect in keeping the graphite in suspension.

I attribute this phenomenon of keeping the graphite in suspension to the formation of a protective colloid, or in other words an action which assists the agar agar in keeping the graphite in suspension either by the Turkey red oil forming additional colloidal material or else in some manner aiding the colloidal effect of the agar. Regardless of what may be true theory underlying my invention, the

foregoing tests as well as others indicate that some markedchange has taken place which has improved the properties of the lubricant.

I Therefore, I do, not wish to be held to any particular theory.

Tov demonstrate the effect of small additions of Turkey red oil on the surface tension of a v graphite-agar agar lubricant, the following experiments were made. Mixtures containing additions ofthe said oil from O to'1.5 5%

were prepared. he surface tension of each, mixture was determined by the capillary tube method. The surface tension was found to decrease with increasing Turkeyred oil conacid on castor oil.

tent, reaching a minimum at about .9% of the oil.

From the foregoing it is apparent that there is a relationship between the surface tension and the amount of graphite held in suspension and the surface tension and the presence of a permanent foam.

In the graphite-agar agar lubricant a permanent foam forms which may be considered as a foam stabilized by the presence of fine particles. of graphite in the interface between the surface film and the remainder of the solution. The Turkey red oil apparently tends to equalize the concentration of the agar agar in the surface film and in the remainder of the solution and, therefore, affects the equilibrium of the surface energy between the two films in such manner that the graphite particles are not absorbed by the interface. Thus the tendency of the graphite particles to stabilize the'foam is removed.

Turkey red oil may be obtained on the market or prepared by the action of sulphuric It is known as an aliphatic sulphur compound and is employed as a mordant in dyeing fabrics. Any other equivalent substance may be employed which will accomplish the desired results.

Modifications of the invention may occur to those skilled in the art but such modifications are contemplated by me as come within the scope of the invention as defined by the appended claims.

What is claimed is:

1. A wire drawing lubricant comprising mixture of powdered graphite, a gelatinous suspending medium composed of agar-agar dissolved in water and Turkey red oil.

2. A wire drawing lubricant comprising a mixture of powdered graphite, a gelatinous suspending'medium composed of agar-agar dissolved in water and from about .75 to 1% by volume of Turkey red oil.

3. A wire drawing lubricant comprising powdered graphite mechanically held in suspension by a gelatinous medium consisting of agar agar boiled in water, and Turkey red oil.

4. The method of preparing a wire drawing lubricant which comprises intimately mixing powdered graphite with boiled agar agar dissolved in water and mixing therewith Turkey red oil. a

In testimony whereof, I have hereunto subscribed my name this 28th day of September,

CHARLES V.. IREDELL. 

